import 'package:comunic/helpers/serialization/conversation_message_serialization_helper.dart';
import 'package:comunic/helpers/serialization/conversations_serialization_helper.dart';
import 'package:comunic/helpers/users_helper.dart';
import 'package:comunic/helpers/websocket_helper.dart';
import 'package:comunic/lists/conversation_messages_list.dart';
import 'package:comunic/lists/conversations_list.dart';
import 'package:comunic/lists/unread_conversations_list.dart';
import 'package:comunic/lists/users_list.dart';
import 'package:comunic/models/api_request.dart';
import 'package:comunic/models/api_response.dart';
import 'package:comunic/models/conversation.dart';
import 'package:comunic/models/conversation_member.dart';
import 'package:comunic/models/conversation_message.dart';
import 'package:comunic/models/displayed_content.dart';
import 'package:comunic/models/new_conversation.dart';
import 'package:comunic/models/new_conversation_message.dart';
import 'package:comunic/models/new_conversation_settings.dart';
import 'package:comunic/models/unread_conversation.dart';
import 'package:comunic/utils/account_utils.dart';
import 'package:comunic/utils/dart_color.dart';
import 'package:dio/dio.dart';
import 'package:meta/meta.dart';

/// Conversation helper
///
/// @author Pierre HUBERT

enum SendMessageResult { SUCCESS, MESSAGE_REJECTED, FAILED }

class ConversationsHelper {
  static final _registeredConversations = Map<int, int>();

  /// Create a new conversation
  ///
  /// Return the ID of the newly created conversation or -1 in case of failure
  Future<int> createConversation(NewConversation settings) async {
    final response =
        await APIRequest(uri: "conversations/create", needLogin: true, args: {
      "name": settings.name ?? "",
      "follow": settings.follow ? "true" : "false",
      "users": settings.members.join(","),
      "color": settings.color ?? ","
    }).addBool("canEveryoneAddMembers", settings.canEveryoneAddMembers).exec();

    if (response.code != 200) return -1;

    return response.getObject()["conversationID"];
  }

  /// Update an existing conversation
  ///
  /// Throws in case of failure
  Future<void> updateConversation(NewConversationsSettings settings) async {
    final request = APIRequest.withLogin("conversations/updateSettings")
        .addInt("conversationID", settings.convID)
        .addBool("following", settings.following);

    // Update conversation settings
    if (settings.isComplete)
      request
          .addString("name", settings.name ?? "")
          .addBool("canEveryoneAddMembers", settings.canEveryoneAddMembers)
          .addString("color", settings.color ?? "");

    await request.execWithThrow();

    // Delete old conversation entry from the database
    await ConversationsSerializationHelper()
        .removeElement((t) => t.id == settings.convID);
  }

  /// Delete a conversation specified by its [id]
  Future<void> deleteConversation(int id) async =>
      await APIRequest.withLogin("conversations/delete")
          .addInt("conversationID", id)
          .execWithThrow();

  /// Download the list of conversations from the server
  ///
  /// Throws an exception in case of failure
  Future<ConversationsList> downloadList() async {
    final response =
        await APIRequest.withLogin("conversations/getList").execWithThrow();

    ConversationsList list = ConversationsList();
    response.getArray().forEach((f) => list.add(apiToConversation(f)));

    // Update the database
    await ConversationsSerializationHelper().setList(list);

    return list;
  }

  /// Get the local list of conversations
  Future<ConversationsList> getCachedList() async {
    final list = await ConversationsSerializationHelper().getList();
    list.sort();
    return list;
  }

  /// Get information about a single conversation specified by its [id]
  Future<Conversation> _downloadSingle(int id) async {
    try {
      final response = await APIRequest(
          uri: "conversations/get_single",
          needLogin: true,
          args: {"conversationID": id.toString()}).execWithThrow();

      final conversation = apiToConversation(response.getObject());

      await ConversationsSerializationHelper()
          .insertOrReplaceElement((c) => c.id == conversation.id, conversation);
      return conversation;
    } on Exception catch (e, s) {
      print("Could not get information about a single conversation ! $e => $s");
      return null;
    }
  }

  /// Get information about a conversation. If [force] is set to false, a
  /// cached version of the conversation will be used, else it will always get
  /// the information from the server. The method throws an [Exception] in
  /// case of failure
  ///
  /// Return value of this method is never null.
  Future<Conversation> getSingle(int id, {bool force = false}) async {
    if (force ||
        !await ConversationsSerializationHelper().any((c) => c.id == id))
      return await _downloadSingle(id);
    else
      return await ConversationsSerializationHelper().get(id);
  }

  /// Get the name of a [conversation]. This requires information
  /// about the users of this conversation
  static String getConversationName(
      Conversation conversation, UsersList users) {
    if (conversation.hasName) return conversation.name;

    String name = "";
    int count = 0;
    for (int i = 0; i < 3 && i < conversation.members.length; i++)
      if (conversation.members[i].userID != userID()) {
        name += (count > 0 ? ", " : "") +
            users.getUser(conversation.members[i].userID).fullName;
        count++;
      }

    if (conversation.members.length > 3) name += ", ...";

    return name;
  }

  /// Search and return a private conversation with a given [userID]. If such
  /// conversation does not exists, it is created if [allowCreate] is set to
  /// true
  ///
  /// Throws an exception in case of failure
  Future<int> getPrivate(int userID, {bool allowCreate = true}) async {
    final response = await APIRequest(
      uri: "conversations/getPrivate",
      needLogin: true,
      args: {
        "otherUser": userID.toString(),
        "allowCreate": allowCreate.toString()
      },
    ).execWithThrow();

    // Get and return conversation ID
    return int.parse(response.getObject()["conversationsID"][0].toString());
  }

  /// Asynchronously get the name of the conversation
  ///
  /// Unlike the synchronous method, this method does not need information
  /// about the members of the conversation
  ///
  /// Throws an exception in case of failure
  static Future<String> getConversationNameAsync(
      Conversation conversation) async {
    if (conversation.hasName) return conversation.name;

    //Get information about the members of the conversation
    final members = await UsersHelper().getList(conversation.membersID);

    return ConversationsHelper.getConversationName(conversation, members);
  }

  /// Turn an API entry into a [Conversation] object
  static Conversation apiToConversation(Map<String, dynamic> map) {
    return Conversation(
        id: map["id"],
        lastActivity: map["last_activity"],
        name: map["name"],
        color: map["color"] == null ? null : HexColor(map["color"]),
        logoURL: map["logo"],
        groupID: map["group_id"],
        members: map["members"]
            .cast<Map<String, dynamic>>()
            .map(apiToConversationMember)
            .toList()
            .cast<ConversationMember>(),
        canEveryoneAddMembers: map["can_everyone_add_members"],
        callCapabilities: map["can_have_video_call"]
            ? CallCapabilities.VIDEO
            : (map["can_have_call"]
                ? CallCapabilities.AUDIO
                : CallCapabilities.NONE),
        isHavingCall: map["has_call_now"]);
  }

  static ConversationMember apiToConversationMember(Map<String, dynamic> map) =>
      ConversationMember(
        userID: map["user_id"],
        lastMessageSeen: map["last_message_seen"],
        lastAccessTime: map["last_access"],
        following: map["following"],
        isAdmin: map["is_admin"],
      );

  /// Parse a list of messages given by the server
  ///
  /// Throws an exception in case of failure
  Future<ConversationMessagesList> _parseConversationMessageFromServer(
      int conversationID, APIResponse response) async {
    response.assertOk();

    // Parse the response of the server
    ConversationMessagesList list = ConversationMessagesList();
    response.getArray().forEach((f) {
      list.add(
        apiToConversationMessage(f),
      );
    });

    // Save messages in the cache
    await ConversationsMessagesSerializationHelper(conversationID)
        .insertOrReplaceAll(list);

    return list;
  }

  /// Refresh the list of messages of a conversation
  ///
  /// Set [lastMessageID] to 0 to specify that we do not have any message of the
  /// conversation yet or another value else
  ///
  /// Throws an exception in case of failure
  Future<ConversationMessagesList> _downloadNewMessagesSingle(
      int conversationID,
      {int lastMessageID = 0}) async {
    // Execute the request on the server
    final response = await APIRequest(
        uri: "conversations/refresh_single",
        needLogin: true,
        args: {
          "conversationID": conversationID.toString(),
          "last_message_id": lastMessageID.toString()
        }).execWithThrow();

    return await _parseConversationMessageFromServer(conversationID, response);
  }

  /// Get older messages for a given conversation from an online source
  ///
  /// Throws in case of failure
  Future<ConversationMessagesList> getOlderMessages({
    @required int conversationID,
    @required int oldestMessagesID,
    int limit = 15,
  }) async {
    // Perform the request online
    final response =
        await APIRequest.withLogin("conversations/get_older_messages", args: {
      "conversationID": conversationID.toString(),
      "oldest_message_id": oldestMessagesID.toString(),
      "limit": limit.toString()
    }).execWithThrow();

    return await _parseConversationMessageFromServer(conversationID, response);
  }

  /// Get new messages for a given conversation
  ///
  /// If [lastMessageID] is set to 0 then we retrieve the last messages of
  /// the conversation.
  /// Otherwise [lastMessageID] contains the ID of the last known message
  ///
  /// Throws in case of failure
  Future<ConversationMessagesList> getNewMessages(
      {@required int conversationID,
      int lastMessageID = 0,
      bool online = true}) async {
    if (online)
      return await _downloadNewMessagesSingle(conversationID,
          lastMessageID: lastMessageID);
    else
      return await ConversationsMessagesSerializationHelper(conversationID)
          .getList();
  }

  /// Send a new message to the server
  Future<SendMessageResult> sendMessage(
    NewConversationMessage message, {
    ProgressCallback sendProgress,
    CancelToken cancelToken,
  }) async {
    final request = APIRequest.withLogin("conversations/sendMessage")
        .addInt("conversationID", message.conversationID)
        .addString("message", message.hasMessage ? message.message : "");

    request.progressCallback = sendProgress;
    request.cancelToken = cancelToken;

    // Check for file
    if (message.hasFile) request.addBytesFile("file", message.file);

    if (message.hasThumbnail)
      request.addBytesFile("thumbnail", message.thumbnail);

    //Send the message
    APIResponse response;
    if (!message.hasFile)
      response = await request.exec();
    else
      response = await request.execWithFiles();

    if (response.code == 401)
      return SendMessageResult.MESSAGE_REJECTED;
    else if (response.code != 200) return SendMessageResult.FAILED;

    return SendMessageResult.SUCCESS;
  }

  /// Save / Update a  message into the database
  Future<void> saveMessage(ConversationMessage msg) async =>
      await ConversationsMessagesSerializationHelper(msg.convID)
          .insertOrReplace(msg);

  /// Remove a message from the database
  Future<void> removeMessage(ConversationMessage msg) async =>
      await ConversationsMessagesSerializationHelper(msg.convID).remove(msg);

  /// Update a message content
  Future<bool> updateMessage(int id, String newContent) async {
    final response = await APIRequest(
        uri: "conversations/updateMessage",
        needLogin: true,
        args: {"messageID": id.toString(), "content": newContent}).exec();

    if (response.code != 200) return false;

    return true;
  }

  /// Delete permanently a message specified by its [id]
  Future<bool> deleteMessage(int id) async {
    // Delete the message online
    final response = await APIRequest(
        uri: "conversations/deleteMessage",
        needLogin: true,
        args: {"messageID": id.toString()}).exec();

    if (response.code != 200) return false;

    return true;
  }

  /// Get the list of unread conversations
  ///
  /// Throws in case of failure
  static Future<UnreadConversationsList> getListUnread() async {
    final list = (await APIRequest.withLogin("conversations/get_list_unread")
            .execWithThrow())
        .getArray();

    return UnreadConversationsList()
      ..addAll(list.map((f) => UnreadConversation(
            conv: apiToConversation(f["conv"]),
            message: apiToConversationMessage(f["message"]),
          )));
  }

  /// Register a conversation : ask the server to notify about updates to the
  /// conversation through WebSocket
  Future<void> registerConversationEvents(int id) async {
    if (_registeredConversations.containsKey(id))
      _registeredConversations[id]++;
    else {
      _registeredConversations[id] = 1;
      await ws("\$main/register_conv", {"convID": id});
    }
  }

  /// Un-register to conversation update events
  Future<void> unregisterConversationEvents(int id) async {
    if (!_registeredConversations.containsKey(id)) return;

    _registeredConversations[id]--;

    if (_registeredConversations[id] <= 0) {
      _registeredConversations.remove(id);
      await ws("\$main/unregister_conv", {"convID": id});
    }
  }

  /// Send a notification to inform that the user is writing a message
  static Future<void> sendWritingEvent(int convID) async =>
      await ws("conversations/is_writing", {"convID": convID});

  /// Turn an API response into a ConversationMessage object
  static ConversationMessage apiToConversationMessage(
    Map<String, dynamic> map,
  ) {
    var file;
    if (map["file"] != null) {
      final fileMap = map["file"];
      file = ConversationMessageFile(
        url: fileMap["url"],
        size: fileMap["size"],
        name: fileMap["name"],
        thumbnail: fileMap["thumbnail"],
        type: fileMap["type"],
      );
    }

    var serverMessage;
    if (map["server_message"] != null) {
      final srvMessageMap = map["server_message"];

      var messageType;
      switch (srvMessageMap["type"]) {
        case "user_created_conv":
          messageType = ConversationServerMessageType.USER_CREATED_CONVERSATION;
          break;

        case "user_added_another":
          messageType = ConversationServerMessageType.USER_ADDED_ANOTHER_USER;
          break;

        case "user_left":
          messageType = ConversationServerMessageType.USER_LEFT_CONV;
          break;

        case "user_removed_another":
          messageType = ConversationServerMessageType.USER_REMOVED_ANOTHER_USER;
          break;

        default:
          throw Exception(
              "${srvMessageMap["type"]} is an unknown server message type!");
      }

      serverMessage = ConversationServerMessage(
        type: messageType,
        userID: srvMessageMap["user_id"],
        userWhoAdded: srvMessageMap["user_who_added"],
        userAdded: srvMessageMap["user_added"],
        userWhoRemoved: srvMessageMap["user_who_removed"],
        userRemoved: srvMessageMap["user_removed"],
      );
    }

    return ConversationMessage(
        id: map["id"],
        convID: map["conv_id"],
        userID: map["user_id"],
        timeSent: map["time_sent"],
        message: DisplayedString(map["message"] ?? ""),
        file: file,
        serverMessage: serverMessage);
  }
}